The present invention relates to synchros, more particularly to methods and devices for generating synchro signals.
Synchros are analog electronic devices that provide angular or similar information pertaining to navigation, communication, detection, weaponry, etc. Synchros have been used for some time in many defense, commercial, and maritime applications, and have been regarded to be reliable, robust, and accurate. Generally speaking, a synchro operates in the manner of a rotary electrical transformer, and serves to measure and set the angle of a rotating device.
Synchro signals are analog signals. A synchro receives synchro signals, and these actuate the synchro. Traditionally, synchro signals are in the form of a three-signal (e.g., three-wire) synchro output representing angular data. For instance, a digital-to-synchro converter may output analog angular data corresponding to binary-coded decimal digital input.
A synchro can implement the analog angular data to set the azimuth of a satellite dish, the direction of an antenna, the angle of a ship rudder, the trajectory of a weapons system, etc. Desired angles may be entered through a computer interface, which sends a digital signal to a digital-to-synchro converter, which in turn generates an equivalent synchro signal to actuate the synchro to the proper angle.
Traditional synchro meters have been used, during installation and onboard troubleshooting, to take five inputs and display an angle representing a unique phase and amplitude of each synchro signal. However, a traditional synchro meter does not generate synchro signals that can be fed into a system for testing purposes.
This functionality—viz., generation of synchro signals—is useful in verifying proper cable connections, testing hardware that receives synchro signals, and testing software that receives digital values from the hardware that converts the synchro signals to digital signals. The tested software may be designed, for instance, to bring about display of numbers, graphics, or boolean data, based on conversion of synchro to a digital format.
The few commercially available synchro generators generate a synchro signal by rotating a rotor to set up different angles. Conventional synchro generators are limited in their inability to generate more than one type of synchro signal, e.g., 1×, 2×, 3×, 4×, 10×, etc. A synchro rotor of 2× design, for instance, cannot be used to input 4× or 1× signals. Therefore, a customer must purchase separate conventional synchro generators according to various requirements.
Furthermore, since conventional synchro generators require an external force in order to rotate, they are incapable of effecting smart simulation of ship parameters such as rudders, speed, revolutions per minute (RPM), or heading. Moreover, conventional synchro generators tend to be large and heavy, lack a display system for verifying output signals vis-à-vis received signals, and cannot generate customized synchro signals (for instance, a rarely used synchro signal such as 0.7×, for which no conventional synchro generators are available).
When any hardware or software is defective, or synchro signals (R1, R2, S1, S2, S3) are not matching at a connection point, the received value may be incorrect, or may damage the recipient hardware. Post-installation testing and troubleshooting may require large amounts of time to determine a wrong cable connection at a junction box or to hardware. In order to avoid problems such as damage to hardware, it is desirable to reduce troubleshooting time or pre-verification time relating to transmission of synchro signals.
In addition, during installation on ships, sources that generate synchro signals are not energized for safety reasons, and hence data received in synchro signal form cannot be verified until the ship's crew powers up the sources. Hence, an additional need is the capability of generating synchro signals during these periods in which sources are unavailable.
An instructive resource on synchros is the Synchro/Resolver Conversion Handbook, Fourth Edition, 1994, Library of Congress Catalog Number 74-77038, Data Device Corporation (DDC), 105 Wilbur Place, Bohemia, N.Y. (electronic version, 125 pages, available in pdf at the DDC website).
Incorporated herein by reference is U.S. Pat. No. 8,193,955 B2, entitled “Modular Units for Synchro-to-Digital Conversion and Digital-To-Synchro Conversion,” issued 5 Jun. 2012, inventor Charles J. Hermann.
Also incorporated herein by reference is co-pending U.S. nonprovisional patent application Ser. No. 13/487,701, entitled “Hybrid Digital-to-Synchro Converter Unit,” filed 4 Jun. 2012, inventor Bhavesh V. Patel.